CN103779271A - Method for etching inverted taper profile - Google Patents
Method for etching inverted taper profile Download PDFInfo
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- CN103779271A CN103779271A CN201210415193.8A CN201210415193A CN103779271A CN 103779271 A CN103779271 A CN 103779271A CN 201210415193 A CN201210415193 A CN 201210415193A CN 103779271 A CN103779271 A CN 103779271A
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- etching
- back taper
- taper profile
- insulating medium
- medium layer
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
- H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
- H01L21/76801—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
- H01L21/76802—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing by forming openings in dielectrics
- H01L21/76804—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing by forming openings in dielectrics by forming tapered via holes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31105—Etching inorganic layers
- H01L21/31111—Etching inorganic layers by chemical means
- H01L21/31116—Etching inorganic layers by chemical means by dry-etching
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31144—Etching the insulating layers by chemical or physical means using masks
Abstract
The invention provides a method for etching an inverted taper profile. The method comprises steps of (a) successively forming a underlying metal connection line and an insulating dielectric layer on a substrate; (b) forming an etching pattern of photoresist on the insulating dielectric layer; (c) performing first-time dry etching on the insulating dielectric layer in order to remove a part of the insulating dielectric layer over the underlying metal connection line and form an opening on the insulating dielectric layer; (d) removing the photoresist in order to expose the top surface of the insulating dielectric layer; and (e) performing second-time dry etching on the insulating dielectric layer in order to remove the residual insulating dielectric layer over the underlying metal connection line and form an intersection angle from 50 to 70 degrees between an etched inclined plane of the insulating dielectric layer and a horizontal plane. The method utilizes two etching process steps including steps of the first-time dry etching, the photoresist removing, and the second-time dry etching so as to obtain a smaller etching angle ingeniously, form inverted taper profile, and acquire a larger metal filling opening.
Description
Technical field
The present invention relates to a kind of lithographic method, particularly a kind of back taper profile lithographic method that reduces etching angle.
Background technology
Dry etching is the technology of carrying out film etching with plasma.In the time that gas exists with plasma form, it possesses two features: on the one hand these aerochemistry specific activity normalities lower time in plasma is eager to excel a lot, according to the difference of the material that is etched, selects suitable gas, just can react with material quickly, realize the object that etching is removed; On the other hand, can also utilize electric field plasma to guide and accelerate, make it possess certain energy, in the time that its bombardment is etched thing surperficial, the atom of the thing material that is etched can be hit, thus reach utilization energy physically and shift to realize the object of etching.Therefore, dry etching is the result of two kinds of process balances of wafer surface physics and chemistry.
Dry etching is divided into again three kinds: physical property etching, chemistry etching, physical chemistry etching.Wherein physical property etching is called again ise.Clearly, this ise is got atom by the bombardment of energy process and sputter are very alike.(imagine, if there is the very old cob wall of one side, firmly kick out with football, the fragment that may just have metope is therefrom peeled off) this extreme dry etching directivity is very strong, can accomplish anisotropic etching, but can not carry out selective etch.
Chemistry etching is utilized the chemism atomic group in plasma and the material generation chemical reaction that is etched, thereby realizes etching object.Due to core or the chemical reaction (just not relating to the gaseous state of solution) of etching, therefore the effect of etching and wet etching are a bit close, have good selectivity, but anisotropy are poor.
People compromise to these two kinds of extreme processes, obtain some physical chemistry lithographic techniques of extensive use up till now.For example reactive ion etching (RIE--Reactive Ion Etching) and high density plasma etch (HDP).These techniques are the physical bombardment to substrate and chemical reaction double action etching by active ion, has the advantage that anisotropy and selectivity are good concurrently simultaneously.RIE has become most widely used main flow lithographic technique in very lagre scale integrated circuit (VLSIC) manufacturing process at present.
Conventionally,, in small-scale integrated circuit (IC) chip or pad design, be difficult to obtain applicable gap and fill copper cash or aluminum steel.Conventionally because gap is less, bring inconvenience to filling metal.Obtain good gap-filling properties and just must obtain relatively sharp-pointed etching angle, specifically, in actual production process, etching angle α is less than 70 ° just can obtain good gap.
And traditional dry etching method is difficult to obtain an applicable metal filled back taper profile.Fig. 1 (a) illustrates traditional dry etching method to 1 (d).(can with reference to the accompanying drawings of in term revise) common dry etching method will experience following four steps:
If Fig. 1 (a) is to as shown in Fig. 1 (d), the object of etching comprises from bottom to up metal level, etching stop layer, oxide skin(coating) and the photoresist layer of stack successively.
The schematic diagram of the initial state in the etching technics that Fig. 1 (a) is prior art;
The schematic diagram of the etching process in the etching technics that Fig. 1 (b) is prior art;
In the etching technics that Fig. 1 (c) is prior art, remove the schematic diagram of the step of photoresist;
In the etching technics that Fig. 1 (d) is prior art, remove the schematic diagram of the step of etching stop layer.
By this technique, the etching angle α finally obtaining is greater than 80 ° conventionally.
Similarly, Fig. 2 (a) illustrates another kind of traditional dry etching method to 2 (d).If Fig. 2 (a) is to as shown in Fig. 2 (d), the object of etching comprises metal level, the first etching stop layer, the first oxide skin(coating), the second etching stop layer, the second oxide skin(coating) and the photoresist layer of stack successively.
The schematic diagram of the initial state in the etching technics that Fig. 2 (a) is prior art;
The schematic diagram of the etching process in the etching technics that Fig. 2 (b) is prior art;
In the etching technics that Fig. 2 (c) is prior art, remove the schematic diagram of the step of photoresist;
In the etching technics that Fig. 2 (d) is prior art, remove the schematic diagram of the step of etching stop layer.
By this technique, similar to the result of Fig. 1, the etching angle α finally obtaining is still greater than 80 ° conventionally.
Prior art, as Japan Patent JP 7050292A and U.S. Pat 4978420A, are all the technology of inventing in order to obtain less etching angle, but practical effect is unsatisfactory.
In view of this, provide one can obtain less etching angle, provide the lithographic method of larger metal filled opening to seem particularly important.
Summary of the invention
For defect of the prior art, the object of this invention is to provide a kind of back taper profile lithographic method, by the processing step of twice etching, for the first time etching, go photoresist, the step of etching for the second time, obtain less etching angle, form back taper profile, obtain larger metal filled opening.
According to an aspect of the present invention, provide a kind of back taper profile lithographic method, comprise the following steps:
(a) on substrate, form successively underlying metal line and insulating medium layer;
(b) on described insulating medium layer, form the photoresist of patterning;
(c) described insulating medium layer is carried out to dry etching for the first time, remove the SI semi-insulation dielectric layer of underlying metal line top, on described insulating medium layer, form opening;
(d) remove photoresist, expose the upper surface of described insulating medium layer;
(e) insulating medium layer is carried out to dry etching for the second time, remove the residue insulating medium layer of underlying metal line top, the angle forming between inclined-plane and the horizontal plane of insulating medium layer after etching is 50 ° to 70 °.
Preferably, in described step (e), the sidewall of described insulating medium layer split shed and the upper surface exposing are bombarded to etching, the cross section of described dielectric split shed forms back taper profile gradually simultaneously.
Preferably, in described step (c), the degree of depth of dry etching is 20% to 80% of insulating medium layer total height for the first time.
Preferably, for the first time dry etching and for the second time dry etching include bombardment etching and multistep chemical etching.
Preferably, the energy of the projectile of the bombardment etching in dry etching is greater than the energy of the projectile of the bombardment etching in dry etching for the first time for the second time.
Preferably, described bombardment etching is with lower one:
Sputter and ion beam milling erosion;
Plasma etching;
High pressure plasma etching;
High density plasma etch; And
Reactive ion etching.
Preferably, in described bombardment etching, its reacting gas is combined as O
2, A
r, CO, CO
2, CHF3, CF
4, C
4f
8, C
4f
6and C
5f
8.
Preferably, described insulating medium layer comprises at least one oxide skin(coating) and at least one etching stop layer, and described etching stop layer is provided with at least one described oxide skin(coating).
Preferably, the speed that described etching stop layer is etched is slower than the speed that described insulating medium layer is etched.
Preferably, described insulating medium layer is followed successively by the first oxide skin(coating) and the first etching stop layer from top to bottom.
Preferably, in described step (c), dry etching has only been removed part the first oxide skin(coating) for the first time, retains residue the first oxide skin(coating) and the first etching stop layer.
Preferably, described insulating medium layer is followed successively by the first oxide skin(coating), the first etching stop layer, the second oxide skin(coating) and the second etching stop layer from top to bottom.
Preferably, dry etching for the first time in described step (c), has removed part the first oxide skin(coating), the first etching stop layer and part the second oxide skin(coating), retains residue the second oxide skin(coating) and the second etching stop layer.
Preferably, afterwards, step (e) also comprises that step (d1) carries out lateral erosion to the first etching stop layer to described step (d) before.
Preferably, the gross thickness of described insulating medium layer is 100nm to 50000nm.
Preferably, the thickness of described photoresist is 100nm to 40000nm.
Preferably, described underlying metal line is aluminum steel or copper cash.
Preferably, the angle between inclined-plane and the horizontal plane of described insulating medium layer after etching is 60
Back taper profile lithographic method of the present invention, by the processing step of twice etching, for the first time etching, go photoresist, the step of etching for the second time, obtain dexterously less etching angle, form back taper profile, obtain larger metal filled opening.
Accompanying drawing explanation
By reading the detailed description of non-limiting example being done with reference to the following drawings, it is more obvious that other features, objects and advantages of the present invention will become:
The schematic diagram of the initial state in the etching technics that Fig. 1 (a) is prior art;
The schematic diagram of the etching process in the etching technics that Fig. 1 (b) is prior art;
In the etching technics that Fig. 1 (c) is prior art, remove the schematic diagram of the step of photoresist;
In the etching technics that Fig. 1 (d) is prior art, remove the schematic diagram of the step of etching stop layer;
The schematic diagram of the initial state in the etching technics that Fig. 2 (a) is prior art;
The schematic diagram of the etching process in the etching technics that Fig. 2 (b) is prior art;
In the etching technics that Fig. 2 (c) is prior art, remove the schematic diagram of the step of photoresist;
In the etching technics that Fig. 2 (d) is prior art, remove the schematic diagram of the step of etching stop layer;
Fig. 3 illustrates according to a specific embodiment of the present invention, the flow chart of back taper profile lithographic method of the present invention;
Fig. 4 (a) illustrates according to a specific embodiment of the present invention, the schematic diagram of initial state in back taper profile lithographic method of the present invention the first embodiment;
Fig. 4 (b) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the first time in back taper profile lithographic method of the present invention the first embodiment;
Fig. 4 (c) illustrates according to a specific embodiment of the present invention, removes the schematic diagram of photoresist in back taper profile lithographic method of the present invention the first embodiment;
Fig. 4 (d) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the second time in back taper profile lithographic method of the present invention the first embodiment;
Fig. 5 illustrates according to a specific embodiment of the present invention, and in back taper profile lithographic method of the present invention the first embodiment, etching forms back taper profile for the second time, reduces the schematic diagram of etching angle;
Fig. 6 (a) illustrates according to a specific embodiment of the present invention, the schematic diagram of initial state in back taper profile lithographic method of the present invention the second embodiment;
Fig. 6 (b) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the first time in back taper profile lithographic method of the present invention the second embodiment;
Fig. 6 (c) illustrates according to a specific embodiment of the present invention, removes the schematic diagram of photoresist in back taper profile lithographic method of the present invention the second embodiment;
Fig. 6 (d) illustrates according to a specific embodiment of the present invention, the schematic diagram that carries out lateral erosion in back taper profile lithographic method of the present invention the second embodiment;
Fig. 6 (e) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the second time in back taper profile lithographic method of the present invention the second embodiment; And
Fig. 7 illustrates according to a specific embodiment of the present invention, and in back taper profile lithographic method of the present invention the second embodiment, etching forms back taper profile for the second time, reduces the schematic diagram of etching angle.
Reference numeral
A is the top of etching opening
B is the bottom of etching opening
K is the projectile direction of motion
α is etching angle
Embodiment
It will be appreciated by those skilled in the art that those skilled in the art can realize described variation example in conjunction with prior art and above-described embodiment, do not repeat them here.Such variation example does not affect flesh and blood of the present invention, does not repeat them here.
Fig. 3 illustrates according to a specific embodiment of the present invention, the flow chart of back taper profile lithographic method of the present invention.As shown in Figure 3, the invention provides a kind of back taper profile lithographic method, comprise the following steps:
(a) on substrate, form successively underlying metal line and insulating medium layer;
(b) on insulating medium layer, form the photoresist of patterning;
(c) insulating medium layer is carried out to dry etching for the first time, remove the SI semi-insulation dielectric layer of underlying metal line top, on insulating medium layer, form opening;
(d) remove photoresist, expose the upper surface of insulating medium layer;
(e) insulating medium layer is carried out to dry etching for the second time, remove the residue insulating medium layer of underlying metal line top, the angle forming between inclined-plane and the horizontal plane of insulating medium layer after etching is 50 ° to 70 °.
The present invention is mainly by twice etching, i.e. etching is for the first time removed photoresist, and etching for the second time, forms back taper profile.Wherein, etching is mainly to carry out etching according to the etching pattern of photoresist for the first time, forms etching opening.And removing after photoresist, because upper surface and the sidewall of insulating medium layer are all exposed in reacting gas, etching is mainly the lateral etching of strengthening etching opening top for the second time, brute force is subdued the top of etching opening, obtain less etching angle, form back taper profile, obtain larger metal filled opening.
In step (e), the sidewall of insulating medium layer split shed and the upper surface exposing are bombarded to etching, the cross section of dielectric split shed forms back taper profile gradually simultaneously.
Insulating medium layer comprises at least one oxide skin(coating) and at least one etching stop layer.
Fig. 4 (a) illustrates according to a specific embodiment of the present invention, the schematic diagram of initial state in back taper profile lithographic method of the present invention the first embodiment.Fig. 4 (b) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the first time in back taper profile lithographic method of the present invention the first embodiment.Fig. 4 (c) illustrates according to a specific embodiment of the present invention, removes the schematic diagram of photoresist in back taper profile lithographic method of the present invention the first embodiment.Fig. 4 (d) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the second time in back taper profile lithographic method of the present invention the first embodiment.If Fig. 4 (a) is to as shown in Fig. 4 (d), insulating medium layer is followed successively by the first oxide skin(coating) and the first etching stop layer from top to bottom.
For Fig. 4 (a), to the structure shown in Fig. 4 (d), in step (c), dry etching has only been removed part the first oxide skin(coating) for the first time, retains residue the first oxide skin(coating) and the first etching stop layer.Remaining for etching for the second time.
Fig. 5 illustrates according to a specific embodiment of the present invention, and in back taper profile lithographic method of the present invention the first embodiment, etching forms back taper profile for the second time, reduces the schematic diagram of etching angle.As shown in Figure 5, the top that wherein A is etching opening, the bottom that B is etching opening, K is the projectile direction of motion, α is etching angle.In etching process for the second time of the present invention, because sidewall and the upper surface of insulating medium layer split shed are all exposed, so comparing the bottom B of etching opening, the top A of etching opening is more easily subject to the bombardment etching of multiple directions, its degree of being bombarded is very high, the degree that the top A of etching opening is etched is also just much larger than the bottom B of etching opening, so within the same etch step time, the top A of etching opening is bombarded repeatedly, form the slope of large opening, and a little less than the bombardment relatively that the bottom B of etching opening is subject to, form little opening slope, therefore whole etching opening forms back taper profile.Compared with the etching angle of corresponding etching angle α and routine techniques, angle is less.
In conjunction with projectile direction of motion K, can find out for the second time in etching, the bombardment etching that is subject to projectile the closer to the opening portion of etching opening is stronger, the top A of etching opening more easily produces obvious lateral etching effect, the bombardment etching that is subject to projectile the closer to etching opening bottom is more weak, the lateral etching effect of the bottom B of etching opening also relatively a little less than.So the back taper profile forming by the present invention is more remarkable, contributes to metal filled needs, and etching opening under traditional etching technics cannot be realized this structure completely.
Fig. 6 (a) illustrates according to a specific embodiment of the present invention, the schematic diagram of initial state in back taper profile lithographic method of the present invention the second embodiment.Fig. 6 (b) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the first time in back taper profile lithographic method of the present invention the second embodiment.Fig. 6 (c) illustrates according to a specific embodiment of the present invention, removes the schematic diagram of photoresist in back taper profile lithographic method of the present invention the second embodiment.Fig. 6 (d) illustrates according to a specific embodiment of the present invention, the schematic diagram that carries out lateral erosion in back taper profile lithographic method of the present invention the second embodiment.Fig. 6 (e) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the second time in back taper profile lithographic method of the present invention the second embodiment.If Fig. 6 (a) is to as shown in Fig. 6 (e), insulating medium layer is followed successively by the first oxide skin(coating), the first etching stop layer, the second oxide skin(coating) and the second etching stop layer from top to bottom.
For Fig. 6 (a) to the structure shown in Fig. 6 (e), dry etching for the first time in step (c), remove part the first oxide skin(coating), the first etching stop layer and part the second oxide skin(coating), retained residue the second oxide skin(coating) and the second etching stop layer.Remaining for etching for the second time.In this process, because etching is different to the etch rate of the first oxide skin(coating) and the first etching stop layer, down can automatically form the lateral etching to the first etching stop layer when etching through ground floor etching stop layer.
Certainly, also can consider in step (d) afterwards in order to realize special technological requirement, step (e) also comprises that step (d1) carries out lateral erosion to the first etching stop layer before.
Fig. 7 illustrates according to a specific embodiment of the present invention, and in back taper profile lithographic method of the present invention the second embodiment, etching forms back taper profile for the second time, reduces the schematic diagram of etching angle.As shown in Figure 7, the top that wherein A is etching opening, the bottom that B is etching opening, K is the projectile direction of motion, α is etching angle.In etching process for the second time of the present invention, because sidewall and the upper surface of insulating medium layer split shed are all exposed, so comparing the bottom B of etching opening, the top A of etching opening is more easily subject to the bombardment etching of multiple directions, its degree of being bombarded is very high, the degree that the top A of etching opening is etched is also just much larger than the bottom B of etching opening, so within the same etch step time, the top A of etching opening is bombarded repeatedly, form the slope of large opening, and a little less than the bombardment relatively that the bottom B of etching opening is subject to, form little opening slope, therefore whole etching opening forms back taper profile.Compared with the etching angle of corresponding etching angle α and routine techniques, angle is less.
In conjunction with projectile direction of motion K, can find out for the second time in etching, the bombardment etching that is subject to projectile the closer to the opening portion of etching opening is stronger, the top A of etching opening more easily produces obvious lateral etching effect, the bombardment etching that is subject to projectile the closer to etching opening bottom is more weak, the lateral etching effect of the bottom B of etching opening also relatively a little less than.So the back taper profile forming by the present invention is more remarkable, contributes to metal filled needs, and etching opening under traditional etching technics cannot be realized this structure completely.
In step (c), the degree of depth of dry etching is 20% to 80% of insulating medium layer total height for the first time.Comparatively speaking.The object of dry etching and the step of carrying out and common etching phase are together for the first time, mainly to carry out etching according to the etching pattern of photoresist, form etching opening, but, the degree of depth of dry etching can not on earth, be only 20% to 80% of insulating medium layer total height for the first time, reserve 80% to 20% during for etching for the second time, can leave the surplus of lateral etching, make etching opening can form back taper profile.
For the first time dry etching and for the second time dry etching include bombardment etching and multistep chemical etching.Similar with conventional lithographic method, etching in the present invention includes bombardment etching and multistep chemical etching, but the etching intensity of bombarding etching in etch step of the present invention is better than the etching intensity of multistep chemical etching, it in the present invention, is mainly the etching opening that forms back taper profile by bombardment etching.
The energy of the projectile of the bombardment etching in dry etching is greater than the energy of the projectile of the bombardment etching in dry etching for the first time for the second time.The present invention is mainly the formation of facilitating back taper profile by the bombardment etching in dry etching for the second time, and the bombardment etching of strengthening in dry etching for the second time more contributes to achieve this end.In actual etching process, can realize by strengthening etching power and/or the pressure etc. of dry etching for the second time.Angle between inclined-plane and the horizontal plane of the described insulating medium layer finally obtaining after etching is most preferred is 60 °.
Bombardment etching is with lower one: sputter and ion beam milling erosion; Plasma etching; High pressure plasma etching; High density plasma etch; And reactive ion etching.Conventional bombardment lithographic method is all applicable to the present invention, these modes that are not limited to list.
In etching, the pressure of bombardment etching is between 30 to 500mT for the first time, and frequency is 2Mhz, 13.56Mhz, and 27Mhz, one of 60Mhz etc., etching power is between 500 to 60000W, etch period depends on etch rate and actual requirement.
For the second time in etching, the pressure of bombardment etching is between 20 to 200mT, frequency is 2Mhz, 13.56Mhz, and one of 27Mhz etc., etching power 500 to 60000W, etch period depend on etch rate and actual requirement.
In bombardment etching, its reacting gas is combined as O
2, A
r, CO, CO
2, CHF3, CF
4, C
4f
8, C
4f
6and C
5f
8.Gas in this reacting gas combination is conventional etching gas, and its effect is known technology, does not repeat them here.The conventional reacting gas of bombardment etching or the flow velocity ratio of reacting gas are all applicable to the present invention, these gases that are not limited to list.
The gross thickness of insulating medium layer is 100nm to 50000nm.Conventional insulating medium layer is all applicable to the present invention, the thickness that is not limited to list.
The thickness of photoresist is 100nm to 40000nm.Conventional photoresist is all applicable to the present invention, the thickness that is not limited to list.And the technique that is applicable to the removal photoresist of this method is to wash away by O2 or O2+CF4, traditional photoresist process that goes all can.
Underlying metal line is aluminum steel or copper cash.Conventional metal connecting line is all applicable to the present invention, the kind that is not limited to list.
Conventionally have an extra step with removing etching stop layer.The method of removing etching stop layer is prior art.
To Fig. 7, and by two specific embodiments, further illustrate the implementation procedure of back taper profile lithographic method of the present invention below in conjunction with accompanying drawing Fig. 4 (a).
The first embodiment
Fig. 4 (a) illustrates according to a specific embodiment of the present invention, the schematic diagram of initial state in back taper profile lithographic method of the present invention the first embodiment.By common process, on substrate, form successively underlying metal line and insulating medium layer, and on described insulating medium layer, form the etching pattern of photoresist.
In the present embodiment, on metal connecting line, cover successively etching stop layer, oxide skin(coating) and photoresist layer.Wherein metal connecting line can be copper cash.The thickness of photoresist layer is 1000nm, and the thickness of oxide skin(coating) is 350nm, and the thickness of etching stop layer is 35nm.
Fig. 4 (b) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the first time in back taper profile lithographic method of the present invention the first embodiment.Described insulating medium layer is carried out to dry etching for the first time, remove the SI semi-insulation dielectric layer of underlying metal line top, on described insulating medium layer, form opening.
The pressure that bombards for the first time etching in dry etching is 100mT, and frequency is 27Mhz, etching power 2000W, the degree of depth of this etching is how many 200nm, oxide skin(coating) is not penetrated, and the thickness of remaining oxide skin(coating) is 150nm, and the thickness of etching stop layer is not 35nm yet.
Fig. 4 (c) illustrates according to a specific embodiment of the present invention, removes the schematic diagram of photoresist in back taper profile lithographic method of the present invention the first embodiment.Remove photoresist, expose the upper surface of described insulating medium layer, can wash away photoresist by O2 or O2+CF4.Traditional photoresist process that goes all can.
Fig. 4 (d) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the second time in back taper profile lithographic method of the present invention the first embodiment.Insulating medium layer is carried out to dry etching for the second time, remove the residue insulating medium layer of underlying metal line top.
The pressure that bombards for the second time etching in dry etching is 200mT, and frequency is 27Mhz, and etching power 10000W removes the residue insulating medium layer of underlying metal line top.In this process, because sidewall and the upper surface of insulating medium layer split shed are all exposed, the top of etching opening is subject to more bombarding etching, and the bombardment etching that the bottom of etching opening is subject to is less, so etching opening has formed back taper profile gradually.
Fig. 5 illustrates according to a specific embodiment of the present invention, and in back taper profile lithographic method of the present invention the first embodiment, etching forms back taper profile for the second time, reduces the schematic diagram of etching angle.As shown in Figure 5, the top that wherein A is etching opening, the bottom that B is etching opening, K is the projectile direction of motion, α is etching angle.In etching process for the second time of the present invention, because sidewall and the upper surface of insulating medium layer split shed are all exposed, the pressure that bombards etching in dry etching is for the second time 200mT, frequency is 27Mhz, under the etching technics of etching power 10000W, so comparing the bottom B of etching opening, the top A of etching opening is more easily subject to the bombardment etching of multiple directions, its degree of being bombarded is very high, the degree that the top A of etching opening is etched is also just much larger than the bottom B of etching opening, so within the same etch step time, the top A of etching opening is bombarded the slope that has formed large opening repeatedly, and the relatively weak little opening slope that forms of the bombardment that the bottom B of etching opening is subject to, therefore whole etching opening forms back taper profile.Compared with the etching angle of corresponding etching angle α and routine techniques, angle is less.In the present embodiment, the etching angle α finally obtaining is 62 °.
In conjunction with projectile direction of motion K, can find out for the second time in etching, the bombardment etching that is subject to projectile the closer to the opening portion of etching opening is stronger, the top A of etching opening more easily produces obvious lateral etching effect, the bombardment etching that is subject to projectile the closer to etching opening bottom is more weak, the lateral etching effect of the bottom B of etching opening also relatively a little less than.So the back taper profile forming by the present invention is more remarkable, contributes to metal filled needs, and etching opening under traditional etching technics cannot be realized this structure completely.
Certainly, concerning those skilled in the art, even the technological parameter in the first embodiment is changed, within still dropping on protection scope of the present invention.
For example: wherein metal connecting line can be aluminum steel.The thickness of photoresist layer is 2000nm, and the thickness of oxide skin(coating) is 800nm, and the thickness of etching stop layer is 70nm.
The pressure that bombards for the first time etching in dry etching is 200mT, and frequency is 27Mhz, etching power 4000W, the degree of depth of this etching is how many 700nm, oxide skin(coating) is not penetrated, and the thickness of remaining oxide skin(coating) is 100nm, and the thickness of etching stop layer is not 70nm yet.
The pressure that bombards for the second time etching in dry etching is 300mT, and frequency is 60Mhz, and etching power 20000W all removes the residue insulating medium layer of underlying metal line top, and the etching angle α finally obtaining may be 63 °.
The second embodiment
Fig. 6 (a) illustrates according to a specific embodiment of the present invention, the schematic diagram of initial state in back taper profile lithographic method of the present invention the second embodiment.By common process, on substrate, form successively underlying metal line and insulating medium layer, and on described insulating medium layer, form the etching pattern of photoresist.
In the present embodiment, on metal connecting line, cover successively the first etching stop layer, the first oxide skin(coating), the second etching stop layer, the second oxide skin(coating) and photoresist layer.Wherein metal connecting line can be copper cash.Wherein, the thickness 200nm of the thickness 1000nm of photoresist layer, the first oxide skin(coating), the first etching stop layer 20nm, the thickness 150nm of the second oxide skin(coating) and the thickness of the second etching stop layer are respectively 35nm.The effect of two-layer etching stop layer is all the etching in order to help to stop front one deck.
Fig. 6 (b) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the first time in back taper profile lithographic method of the present invention the second embodiment.
The pressure that bombards for the first time etching in dry etching is 300mT, frequency is 27Mhz, etching power 1500W, the degree of depth of this etching is how many 260nm, the first oxide skin(coating) and the first etching stop layer are all through, and the second oxide skin(coating) is through a little, the thickness of the second remaining oxide skin(coating) is 110nm, and the thickness of etching stop layer is not 35nm yet.
Fig. 6 (c) illustrates according to a specific embodiment of the present invention, removes the schematic diagram of photoresist in back taper profile lithographic method of the present invention the second embodiment.Remove photoresist, expose the upper surface of described insulating medium layer, can wash away photoresist by O2 or O2+CF4.Traditional photoresist process that goes all can.In this process, because etching is different to the etch rate of the first oxide skin(coating) and the first etching stop layer, down can automatically form the lateral etching to the first etching stop layer when etching through ground floor etching stop layer.
Fig. 6 (d) illustrates according to a specific embodiment of the present invention, the schematic diagram that carries out lateral erosion in back taper profile lithographic method of the present invention the second embodiment.This can step be possibility, is not steps necessary, carries out lateral erosion and can strengthen the lateral etching to the first etching stop layer.
Fig. 6 (e) illustrates according to a specific embodiment of the present invention, the schematic diagram of etching for the second time in back taper profile lithographic method of the present invention the second embodiment.Insulating medium layer is carried out to dry etching for the second time, remove the residue insulating medium layer of underlying metal line top.
The pressure that bombards for the second time etching in dry etching is 80mT, and frequency is 27Mhz, etching power 5000W.The residue insulating medium layer of underlying metal line top is all removed.In this process, because sidewall and the upper surface of insulating medium layer split shed are all exposed, the top of etching opening is subject to more bombarding etching, and the bombardment etching that the bottom of etching opening is subject to is less, so etching opening has formed back taper profile gradually.
Fig. 7 illustrates according to a specific embodiment of the present invention, and in back taper profile lithographic method of the present invention the second embodiment, etching forms back taper profile for the second time, reduces the schematic diagram of etching angle.As shown in Figure 7, the top that wherein A is etching opening, the bottom that B is etching opening, K is the projectile direction of motion, α is etching angle.In etching process for the second time of the present invention, because sidewall and the upper surface of insulating medium layer split shed are all exposed, the pressure that bombards etching in dry etching is for the second time 80mT, frequency is 27Mhz, under the etching technics of etching power 5000W, so comparing the bottom B of etching opening, the top A of etching opening is more easily subject to the bombardment etching of multiple directions, its degree of being bombarded is very high, the degree that the top A of etching opening is etched is also just much larger than the bottom B of etching opening, so within the same etch step time, the top A of etching opening is bombarded the slope that has formed large opening repeatedly, and the relatively weak little opening slope that forms of the bombardment that the bottom B of etching opening is subject to, therefore whole etching opening forms back taper profile.Compared with the etching angle of corresponding etching angle α and routine techniques, angle is less.In the present embodiment, the etching angle α finally obtaining is 60 °.
In conjunction with projectile direction of motion K, can find out for the second time in etching, the bombardment etching that is subject to projectile the closer to the opening portion of etching opening is stronger, the top A of etching opening more easily produces obvious lateral etching effect, the bombardment etching that is subject to projectile the closer to etching opening bottom is more weak, the lateral etching effect of the bottom B of etching opening also relatively a little less than.So the back taper profile forming by the present invention is more remarkable, contributes to metal filled needs, and etching opening under traditional etching technics cannot be realized this structure completely.
The range of application of the second embodiment is identical with the range of application of the first embodiment, and last obtained etching angle is also roughly the same.
Certainly, concerning those skilled in the art, even the technological parameter in the second embodiment is changed, within still dropping on protection scope of the present invention.
For example: wherein metal connecting line can be copper cash, the thickness 1500nm of photoresist layer, the thickness 400nm of the first oxide skin(coating), the first etching stop layer 30nm, the thickness 350nm of the second oxide skin(coating) and the thickness of the second etching stop layer are respectively 60nm.The effect of two-layer etching stop layer is all the etching in order to help to stop front one deck.
The pressure that bombards for the first time etching in dry etching is 500mT, frequency is 27Mhz, etching power 30000W, the degree of depth of this etching is how many 500nm, the first oxide skin(coating) and the first etching stop layer are all through, and the second oxide skin(coating) is through a little, the thickness of the second remaining oxide skin(coating) is 280nm, and the thickness of etching stop layer is not 60nm yet.
The pressure that bombards for the second time etching in dry etching is 200mT, and frequency is 27Mhz, etching power 20000W.The residue insulating medium layer of underlying metal line top is all removed, and the etching angle α finally obtaining may be 61 °.
In summary, back taper profile lithographic method of the present invention, by the processing step of twice etching, for the first time etching, go photoresist, the step of etching for the second time, obtain dexterously less etching angle, form back taper profile, obtain larger metal filled opening.
Above specific embodiments of the invention are described.It will be appreciated that, the present invention is not limited to above-mentioned specific implementations, and those skilled in the art can make various distortion or modification within the scope of the claims, and this does not affect flesh and blood of the present invention.
Claims (18)
1. a back taper profile lithographic method, is characterized in that, comprises the following steps:
(a) on substrate, form successively underlying metal line and insulating medium layer;
(b) on described insulating medium layer, form the photoresist of patterning;
(c) described insulating medium layer is carried out to dry etching for the first time, remove the SI semi-insulation dielectric layer of underlying metal line top, on described insulating medium layer, form opening;
(d) remove photoresist, expose the upper surface of described insulating medium layer;
(e) insulating medium layer is carried out to dry etching for the second time, remove the residue insulating medium layer of underlying metal line top, the angle forming between inclined-plane and the horizontal plane of insulating medium layer after etching is 50 ° to 70 °.
2. back taper profile lithographic method according to claim 1, it is characterized in that: in described step (e), the sidewall of described insulating medium layer split shed and the upper surface exposing are bombarded to etching, the cross section of described dielectric split shed forms back taper profile gradually simultaneously.
3. back taper profile lithographic method according to claim 1, is characterized in that: in described step (c), the degree of depth of dry etching is 20% to 80% of insulating medium layer total height for the first time.
4. back taper profile lithographic method according to claim 1, is characterized in that: for the first time dry etching and for the second time dry etching include bombardment etching and multistep chemical etching.
5. back taper profile lithographic method according to claim 4, is characterized in that: the energy of the projectile of the bombardment etching in dry etching is greater than the energy of the projectile of the bombardment etching in dry etching for the first time for the second time.
6. back taper profile lithographic method according to claim 5, is characterized in that: described bombardment etching is with lower one:
Sputter and ion beam milling erosion;
Plasma etching;
High pressure plasma etching;
High density plasma etch; And
Reactive ion etching.
7. back taper profile lithographic method according to claim 6, is characterized in that: in described bombardment etching, its reacting gas is combined as O
2, A
r, CO, CO
2, CHF
3, CF
4, C
4f
8, C
4f
6and C
5f
8.
8. back taper profile lithographic method according to claim 1, is characterized in that: described insulating medium layer comprises at least one oxide skin(coating) and at least one etching stop layer, described etching stop layer is provided with at least one described oxide skin(coating).
9. back taper profile lithographic method according to claim 8, is characterized in that: the speed that described etching stop layer is etched is slower than the speed that described insulating medium layer is etched.
10. back taper profile lithographic method according to claim 8, is characterized in that: described insulating medium layer is followed successively by the first oxide skin(coating) and the first etching stop layer from top to bottom.
11. back taper profile lithographic methods according to claim 9, is characterized in that: in described step (c), dry etching has only been removed part the first oxide skin(coating) for the first time, retain residue the first oxide skin(coating) and the first etching stop layer.
12. back taper profile lithographic methods according to claim 8, is characterized in that: described insulating medium layer is followed successively by the first oxide skin(coating), the first etching stop layer, the second oxide skin(coating) and the second etching stop layer from top to bottom.
13. back taper profile lithographic methods according to claim 12, it is characterized in that: dry etching for the first time in described step (c), remove part the first oxide skin(coating), the first etching stop layer and part the second oxide skin(coating), retained residue the second oxide skin(coating) and the second etching stop layer.
14. back taper profile lithographic methods according to claim 13, is characterized in that: afterwards, step (e) also comprises that step (d1) carries out lateral erosion to the first etching stop layer to described step (d) before.
15. back taper profile lithographic methods according to claim 1, is characterized in that: the gross thickness of described insulating medium layer is 100nm to 50000nm.
16. back taper profile lithographic methods according to claim 1, is characterized in that: the thickness of described photoresist is 100nm to 40000nm.
17. back taper profile lithographic methods according to claim 1, is characterized in that: described underlying metal line is aluminum steel or copper cash.
18. back taper profile lithographic methods according to claim 1, is characterized in that: the angle between inclined-plane and the horizontal plane of described insulating medium layer after etching is 60 °.
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| CN104326440A (en) * | 2014-10-31 | 2015-02-04 | 中国科学院光电技术研究所 | Manufacturing method of micro-nano structure capable of accurately controlling depth |
| CN106379858A (en) * | 2016-11-25 | 2017-02-08 | 苏州工业园区纳米产业技术研究院有限公司 | Manufacturing method of micro-electromechanical device, micro-electromechanical device and micro-electromechanical device base structure |
| CN108751123A (en) * | 2018-05-21 | 2018-11-06 | 赛莱克斯微系统科技（北京）有限公司 | A kind of forming method of contact hole |
| WO2023045049A1 (en) * | 2021-09-27 | 2023-03-30 | 北京超弦存储器研究院 | Method for etching mask of magnetic tunnel junction |
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| CN1525533A (en) * | 2003-02-24 | 2004-09-01 | 友达光电股份有限公司 | Method for forming contact hole |
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| US4806199A (en) * | 1985-10-14 | 1989-02-21 | Sgs Microelettronica S.P.A. | (RIE) Plasma process for making metal-semiconductor ohmic type contacts |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104326440A (en) * | 2014-10-31 | 2015-02-04 | 中国科学院光电技术研究所 | Manufacturing method of micro-nano structure capable of accurately controlling depth |
| CN106379858A (en) * | 2016-11-25 | 2017-02-08 | 苏州工业园区纳米产业技术研究院有限公司 | Manufacturing method of micro-electromechanical device, micro-electromechanical device and micro-electromechanical device base structure |
| CN108751123A (en) * | 2018-05-21 | 2018-11-06 | 赛莱克斯微系统科技（北京）有限公司 | A kind of forming method of contact hole |
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| WO2023045049A1 (en) * | 2021-09-27 | 2023-03-30 | 北京超弦存储器研究院 | Method for etching mask of magnetic tunnel junction |
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Address after: 201201 No. 188 Taihua Road, Jinqiao Export Processing Zone, Pudong New Area, Shanghai Patentee after: Medium and Micro Semiconductor Equipment (Shanghai) Co., Ltd. Address before: 201201 No. 188 Taihua Road, Jinqiao Export Processing Zone, Pudong New Area, Shanghai Patentee before: Advanced Micro-Fabrication Equipment (Shanghai) Inc. |